If I leave tomato router GUI on "Bandwidth Real-Time" or "IP TRAFFIC->Real time", slowly % disk activity active time is increasing until it eventually reach 100%. Could this be a bug? If so, why is it fine for me to leave transmission GUI while downloading and not having high disk activity. For the moment, I decided, to avoid having that graph displayed for long as an immediate solution.
Ignore this, if this is not tomato issue design